Effects of the spinal cord section and of subsequent denervation on the mechanical properties of fast and slow muscles.

The Soleus muscle of the rat, 3--6 months old, becomes significantly faster than in the controls, if the spinal cord is cut at birth. Mechanical properties of Extensor Digitorum Longus (EDL) muscle are not altered by spinal cord section. In cordotomized animals Soleus muscle always remains slower than EDL muscle. Denervation, performed 3--6 months after birth, has the same slowing effects in the Soleus and EDL muscles, both in cordotomized and in the control animals.     

Glutamine synthetase activity in subdivisions of brain of the shark, Squalus acanthias

Specific activity of glutamine synthetase in Squalus acanthias (spiny dogfish) central nervous system regions was highest in the cerebellum and lowest in the spinal cord. The levels of activity may relate to the excitability of each region by regulating the glutamate pool.     

Unexpected features of the interaction between individual primary afferents and spinal motoneurones

Summary Simultaneous intracellular recording from spinal motoneurone and dorsal root fibres afferent to it in the isolated amphibian cord revealed a specific correlation between the slow spontaneous depolarizing activity in motoneurones and primary afferents.     

Unexpected features of the interaction between individual primary afferents and spinal motoneurones.

Simultaneous intracellular recording from spinal motoneurone and dorsal root fibres afferent to it in the isolated amphibian cord revealed a specific correlation between the slow spontaneous depolarizing activity in motoneurones and primary afferents.     

Effects of the spinal cord section and of subsequent denervation on the mechanical properties of fast and slow muscles

Summary The Soleus muscle of the rat, 3–6 months old, becomes significantly faster than in the controls, if the spinal cord is cut at birth. Mechanical properties of Extensor Digitorum Longus (EDL) muscle are not altered by spinal cord section. In cordotomized animals Soleus muscle always remains slower than EDL muscle. Denervation, performed 3–6 months after birth, has the same slowing effects in the Soleus and EDL muscles, both in cordotomized and in the control animals.     

Spontaneous miniature potentials in primary afferent fibres

Summary Intracellular recording from primary afferent fibres of the isolated frog spinal cord revealed the existence of spontaneous synaptic activity, related probably to the firing of presynaptic inhibitory fibres.     

Spontaneous miniature potentials in primary afferent fibres.

Intracellular recording from primary afferent fibres of the isolated frog spinal cord revealed the existence of spontaneous synaptic activity, related probably to the firing of presynaptic inhibitory fibres.     

Calcium and magnesium deficiency-induced atrophy of muscle and calcium accumulation in the spinal cord

After severe dietary calcium-magnesium deficiency in rats, succinic dehydrogenase and acetylcholinesterase enzyme activity of gastrocnemius muscle showed a neurogenic atrophy. This alteration was associated with a high concentration of calcium in the spinal cord.     

Transplantation into the mammalian adult spinal cord

Summary Embryonic cerebral cortical tissue obtained from rat embryos of 15-day gestation was transplanted into the cervical spinal cord of adult rats. The cortical transplants survived, grew, and established connections with the host animal's spinal cord. In other animals, knife lesions were first made in the host's spinal cord, and then embryonic cortical tissue was transplanted into the site of the lesion. The cortical transplants in these animals were observed to become an integral part of the host animal's spinal cord.     

Localization of substance P in the nervous system of the human fetus : preliminary results

Substance P (SP) immunoreactive structures were localized by immunofluorescence technique within the central nervous system of human fetuses (12, 15, 19 and 24 weeks old). Specificity of the anti-SP serum was established by immunocytology and radio-immunology. A wide distribution of SP positive structures (pericaryons and/or fibres) was found in brain, spinal cord and dorsal root ganglia. Mesencephalon, pons and dorsal horns of the spinal cord showed very intense fluorescence. The preliminary observations are the first report concerning SP ontogeny in the Human central nervous system. However, it was difficult to ascribe a significance to this neuropeptide during fetal life.     

Stem cells from human apical papilla decrease neuro-inflammation and stimulate oligodendrocyte progenitor differentiation via activin-A secretion

Secondary damage following spinal cord injury leads to non-reversible lesions and hampering of the reparative process. The local production of pro-inflammatory cytokines such as TNF-α can exacerbate these events. Oligodendrocyte death also occurs, followed by progressive demyelination leading to significant tissue degeneration. Dental stem cells from human apical papilla (SCAP) can be easily obtained at the removal of an adult immature tooth. This offers a minimally invasive approach to re-use this tissue as a source of stem cells, as compared to biopsying neural tissue from a patient with a spinal cord injury. We assessed the potential of SCAP to exert neuroprotective effects by investigating two possible modes of action: modulation of neuro-inflammation and oligodendrocyte progenitor cell (OPC) differentiation. SCAP were co-cultured with LPS-activated microglia, LPS-activated rat spinal cord organotypic sections (SCOS), and LPS-activated co-cultures of SCOS and spinal cord adult OPC. We showed for the first time that SCAP can induce a reduction of TNF-α expression and secretion in inflamed spinal cord tissues and can stimulate OPC differentiation via activin-A secretion. This work underlines the potential therapeutic benefits of SCAP for spinal cord injury repair.     

Lipofuscin accumulation in squirrel monkey spinal cord consequent to protein malnutrition during gestation.

The formation of lipofuscin pigment in the anterior horn cells of the cervical spinal cord has shown in the fetuses and neonates under the extrinsic influence of maternal protein deprivation during the gestation period in the squirrel monkeys.     

Spontaneous morphine withdrawal from the rat spinal cord

A characteristic and reproducible sign of narcotic withdrawal is the naloxone induced increase in arterial pressure. In morphine-dependent rats allowed to undergo spontaneous withdrawal (6-24 h) and then transected at the spinal C-1 level, arterial pressure was maintained at a significantly higher level than either spinal-transected nondependent controls or morphine-dependent, spinal-transected rats pithed from C-1 to L-4. These findings indicate that the morphine-dependent spinal cord, independent of supraspinal influences, is able to exhibit an autonomic component of spontaneous withdrawal.     

疼痛的神经生物学--理解大脑机制及神经疾病治疗的机理

中枢神经系统的神经元和突触具有可塑性，他们能够发生贯穿整个生命过程的长时程改变。研究这种长时程变化的分子和细胞学机制，不仅可以帮助我们了解大脑如何学习和储存新的知识，而且还可以揭示机体损伤后病理变化的机制。我认为，一方面学习和记忆等生理学功能的神经机制可能与大脑在疼痛期间的反常或机体损伤相关的变化过程共用一些信号分子；另一方面，一些不参与认知学习和记忆过程的突触和神经元网络机制也可能与疼痛的病理过程相关。伤害性感受可以从脊髓传递到前脑并在不同水平受到调节。其中，前扣带脑皮质(anterior cingulate cortex，ACC)在痛觉的感受和调节中具有重要作用。我们的实验结果表明，ACC中的N-甲基-D-门冬氨酸(NMDA)受体依赖的、钙／钙调蛋白激活的腺苷酸环化酶(adenylyl cyclases，AC)(ACl和ACB)在慢性痛的表达过程中起着重要的作用。ACC还可以通过激活内源性易化系统影响脊髓背角的痛觉信号传递。这些结果为机体对损伤的生理反应如痛行为反应、情绪变化和不良记忆等提供了重要的突触和分子水平的机制。加强对疼痛机制研究，会带动中国的神经科学的基础和临床研究。     

Dog behaviour as related to spinal cord temperature.

3 dogs could behaviourally modify their own spinal cord temperature (Tspin. cord). In a hot environment, 2 dogs did not cool their spinal cord, 1 dog warmed it. The higher the environmental temperature, the higher the chosen Tspin. cord. These results seem to imply that this latter dog tended, in warm environment, to behaviourally reduce: Ts greater than Tspin. cord (Ts mean skin temperature). Data obtained previously support this explanation.     

Post-tetanic changes of bilateral dorsal root potentials evoked by stimulation of the cutaneous afferents.

In spinal cats following tetanic stimulation of the cutaneous nerve bilateral dorsal root potentials in the lumbar spinal cord are depressed. Because of differences between ipsi- and contralateral potentials, this depression can usually be evoked only on one side of the cord.     

Degenerative atrophy of central terminals of primary sensory neurons induced by blockade of axoplasmic transport in peripheral nerves

Summary Perineural colchicine- or vinblastine-treatment results in disappearance of non-lysosomal acid phosphatase activity, characterizing axon terminals in the Rolando substance of the normal spinal cord. Ultrastructural alterations are identical with those seen in the course of degenerative atrophy.Supported by research grant No. 4-01-0303-01-1 from the Hungarian Ministry of Health.     

成年大鼠脊髓损伤后内源性神经前体细胞的增殖与分化规律的研究

目的观察成年大鼠脊髓损伤后内源性神经前体细胞的增殖与分化,探讨内源性神经前体细胞的自然变化规律。方法制作脊髓压迫损伤模型,Brdu腹腔注射标记神经前体细胞,免疫荧光法(Immunofluoreseence)检测大鼠脊髓Brdu、GFAP、MBP阳性细胞数的变化。结果 1)正常组可观察到少量Brdu阳性细胞,脊髓损伤后Brdu阳性细胞显著增加(p0.05),并在第7天达到最大值,21天时仍高水平表达。2)正常组可见少量Brdu/GFAP和Brdu/MBP阳性细胞,脊髓损伤后Brdu/GFAP,Brdu/MBP双标阳性细胞数显著增加(p0.05)。结论脊髓损伤后神经前体细胞的数量在第7天达到最大值,我们认为,一周内可能是神经前体细胞增殖分化调控的关键时期。此外,新生星形胶质细胞和少突胶质细胞大量增殖,并与神经前体细胞的迁移、后肢功能恢复表现出一定的同步性,提示新生胶质细胞可能参与了脊髓损伤后神经功能的修复作用。     

Post-tetanic changes of bilateral dorsal root potentials evoked by stimulation of the cutaneous afferents

Summary In spinal cats following tetanic stimulation of the cutaneous nerve bilateral dorsal root potentials in the lumbar spinal cord are depressed. Because of differences between ipsi- and contralateral potentials, this depression can usually be evoked only on one side of the cord.     

Vestibular units during decompensation.

Typical modifications of the unitary discharge of vestibular units have been recorded following the transection of the spinal cord of hemilabyrinthectomized and compensated guinea-pigs. These results support the concept that the spinal cord is essential in the compensation of the symptoms resulting from a lesion of one labyrinth.